Method of and means for protecting the bores of heavy guns from erosion.



F. N. DU BOIS.

METHOD OF AND MEANS FOR PROTECTING THE BORES OP HEAVY GUNS FROM EROSION.

APPLIGATIOH' FILED APR. 25, 1910.

Patented Nov. 12, 1912.

IX) i/bwa-oaeo Maw "UNITED STATES Paras EEC;

FREDERICK N. DU BOIS, OF NEW YORK, N. Y.

'hiIETHOID or means ron rn'o'rncrmc THE BORES or HEAVY cons FROMEROSION.

Specification of Letters Patent.

Patented Nov. 12, 1912.

To all whom it may concern Be it known that I, FREDERICK N. DU

Bors, a citizen of the United States, and a resident of the borough ofManhattan, in

the county, city, and State of'New York, have invented certain new anduseful Improvements in the Method of and Means for Protecting the Boresof Heavy Guns from Erosion, of which the, following is a speci fication.In the use of heavy guns of the modern high power class'it has beenfound, that, at each discharge, the walls of the bore, when a projectileis employed, are so eroded either by the enormous pressure to which theyaresubjected by the gas evolved in the burning of the explosive, or bythe heat liberated thereby, or by both together, that after a certainnumber of discharges, usually less than'one hundred, the walls of thebore are so eaten away as to render the gun moperative and incapable offurther use, until the same is re-bored, a bushing supplied, and the gunre-rifled, which, in consequence of the necessity to dismount the gunand transportit to the factory, is an operation that notonlyinvolves'much time, but great expense as well.

The object of my invention is therefore, to obviate this defect; and, tothis end, the invention ,consists in the method of and means forapplying a coating of metal under pressure to the eroded portions of thewalls of the bore at or after each discharge of the gun, whereby a freshmetallic surface ispresented thereby to the action of the gases andbeat, all' as will hereinafter more fully appear. I 7

Referring to the accompanying drawing, which forms a part of thisspecification, Figure 1, is a side elevation, partly in axial section,of a portion of a gun, showing in side elevationa projectile constructedin accordance with my invention, and a cartridge arranged in the chamberin rear thereof; Fig. 2, a side elevation of a projectile constructed inaccordance with my invention. wit-ha portion at its butt broken away andshown in section,to more clearly illustrate the invention, and Fig. 3,an enlarged sectional fragment of the butt of a projectile, showing thearrangement of the abrasion band thereon. V

In the several figures, like letters of ref,

erence are employed to designate corresponding parts.

A indicates the rear or breech portion of a cannon or other piece ofheavyordna-nce, which is or may be constructed of any ordinary or wellknown form. As shown in the drawing however, it follows the general lineof construction of the ordinary modern breech-loading high powergun,'and is provided with the usual rifled bore a and breech opening andclosing mechanism (not shown), and also with a charge-receiving chambera at the rear end of the bore a, as is common with guns of thischaracter as ordinarily employed. In being thus constructed, the gun,when in operation, receives within the chamber a the required charge,comprising the projectile B and the bag of explosive C; and thedischarge of the projectile therefrom is effected by burning theexplosive within the bore a and chamber oi the result of which is togenerate a sufiicient volume of gas and set free the requisite amount ofheat to violently expel the projectile from-the bore of the gun andcarry it forward in its trajectory to its place of destination. Toaccomplish this ejection and propulsion of the projectile at theexcessively high speed and to the great distance desired, it is obviousthat the pressure exerted by the consumption of the explosive within theboreof the gun is enormous and exceeds at times more than fifteen, ifnot twenty, tons to the square inch.

With guns of the present high power class and with the use of modernsmokeless and other excessively strong acting explosives, the pressureexerted by its consump tion is so extremely great, that in ejecting theprojectile from the gun and carrying it forward in its flight, it actsupon the walls of the bore a with such a tremendous force that it erodesand eats them away to such an. extent as to completely obliterate thelands a between the grooves a of the rifling, and render the gun whollyuseless after a certain number of shots have been exceed one hundredshots in all. I have discovered however that this erosion and eatingaway of the walls of the bore may be obviated in whole or in part,by-applying fired, which, in practice, seldom or never 7.

'to the surfaces of these walls, a metallic coating under pressure at orbefore each discharge of the gun in which a projectile is, or is to be,employed. While the metals that may be adopted to this end are ofvarious kinds, I have found that bronze, made up as an alloy from copperand tin is the most efiicient for the purpose, since when forced againststeel surfaces under great pressure, it adheres thereto so firmly andtenaciously as to almost aniount to an actual weld, and when applied tothe walls of the ing band 5 and supports the bronze coating material,which is preferably'made in the form of a ring'b and is disposed in asuitable groove formed circumferentially around the conical body 6, inrear of the groove engaging band 6 as shown. This ring if, which, forconvenience of description I shall hereinafter designate an abrasionring, is preferably though not necessarily made of the same diameter asthe groove-engaging band 5 whereby to engage with the lands of, and, atthe same time be pressed against the bottom of the grooves o in movingalong the bore a, as the projectile is ejected from the gun. In beingthus engaged with the lands a and pressed out ward against the bottom ofthe grooves (1 it is obvious that-the abrasion ring 0 in being carriedforward by the projectile over any roughened or eroded surface in thewalls of the bore a, will be engaged thereby and the portions thereofthus engaged will be abraded away by such engagen'ient, with the resultthat the portions of the material thus abraded and carried away will, inconsequence of the pressure exerted between the ring and the walls ofthe bore, be forced into the depressions formed. in the walls of the bre by such erosi n and thereby adhere so firmly to the material of thegun to form a practically fixed surface of this bronze material upon theinterior of the bore over the roughened portion thereof, against whichthe gases and heat may act. at the next discharge of the gu n. In ordertherefore to provide for pressing this abrasion ring D out-ward intocontact'with the walls of the bore a with the requisite degree ofpressure, the groove 6 in which the ring is located, instead of beingmade with vertical side walls, has its front walls 6 inclined forwardfrom its inner to its outer edge, uhcreby to act as an expandward uponthe inclined walls of the groove 71 when the explosive is consumed, therear walls 6 of this groove are inclined rear-' wardly to a slightdegree from their inner to their outer edges, with an annular rabbet Z)formed around their outer edge, whereby to permit of the engagement ofappropriate tongs or other retracting means with the projectile when thewithdrawal of the latter from the gun. is desired. \Vith the rear wallsof the groove b 'thus backwardly,

inclined, the free action of the gases evolved by the eonsumptionof theexplosive against the rear edge of the abrasion ring b throughout itsentire extent is permitted; and, in order to allow of the forwardmovement of this ring upon the inclined walls I)" of the groove 6 andwith a View to preventing it from fixedly adhering to the body 6 oftheprojectile when acted upon by the gases and heat, the groove 6 is madesomewhat wider than the ring 6 and a layer of lubricating material N,such, for instance, as graphite or plumbago is interposed between thefront edge of the ring and the forward inclined walls (2* of the grooveb,

as shown. With the abrasion ring 19 thus supported and carried by theprojectile, a metallic coating is applied to any eroded or otherwiseroughened surface that may be present within the bore a and firmly adhered or secured thereto at each discharge of a projectile from the gun.In the construction of the abrasion ring b the mate'- rial of which itis composed, while possessed I of; a less degree of hardness than thematerial of the gun itself, is preferably somewhat harder than thegroove-engaging band 6 whereby to resist the scraping action of thisgroove-engaging band in passing over and in contact with the material ofthe abrasion ring previously applied as a coating to the eroded or otherroughenedsurfaces of the bore a. lVith the abrading ring 6 thus securedto and carried by the projectile B, the walls of the bore of the gunwill be unaffected thereby when it is passed over them and the walls arefree: from erosion or other roughness. W'hen however-these walls areeroded or otherwise roughened, then in the abrading ring being carriedforward over them by the projectile, the abrasion of this ring by theroughness ofv the walls will be effected, and the portion thereof thusabraded away will be deposited in the depressions formed by suchroughness and firmly adhered or secured therein, with the result thatthe portions thus coated with 7 the abraded material will present asmooth surface to the action of the gases and the heat respectirelygenerated and set free at the next dischar e of the gun, and so on.

From the foregoing therefore it will be seen, that I not only protectthe bore of'a gini from erosion by the action of the gases and heatrespectively generated and set free by the discharge of the gun, butalso provide means by which that protection is effected.

Having thus described the invention, and specified certain of the Waysin which it is or may be carried into effect, I claimand desire tosecure by Letters Patent of the ened and eroded surface portions as theprojecile is forced through the gun bore, the

abraded portions of said encircling member a being applied to the gunbore under pressure substantially at the time it is abraded.

In testimony whereof, I have hereunto set 35 my hand in the presence oftwo Witnesses this 19th day of April, 1910.

FREDERICK N. DU BOIS.

Witnesses:

THOMAS GANNON, GRACE T. DIXON.

